The present invention relates to an apparatus for winding electrical coils with closed cores of the type having a coil former receiver provided on a support, a wire supply device, and loading and unloading stations for unwound and wound cores respectively.
In known ring core coil-winding devices, wherein annular magazines that are guided through the core opening are rotatably mounted and circulate around the coil formers, the wire runs from the magazine to the coil former over a wind-off roller. These devices are only suitable for relatively large ring cores. Typically, cores with an outer diameter of about 20 mm are considered to be the smallest size that such a device can accomodate.
In order to wind small ring cores having an annular core outer diameter of 16 mm or less, a semi-automatic winding method and an apparatus has been disclosed in European Patent Application No. 0068 415. In the disclosed system, the wire is wound on the core by means of a magnetizable needle fixed to the lead end of the winding wire. The needle is guided under the action of a magnetic field along a closed orbit that extends partly through the core opening and that is reduced in length as the winding period increases.
However, due to the use of magnets to guide the needle, such a winding device is not suitable for extremely small cores, for example for video core coils having an outer core diameter of the order of about 3 mm and a core opening of about 0.35 mm.